Continuous mining machine



July 5, 1966 J. GONSK] 3,259,436

CONTINUOUS MINING MACHINE Filed March 28, 1961 5 Sheets-Sheet 1 INVENTOR. Jose ck gawsz' {fills July 5, 1966 J. GONSKI CONTINUOUS MINING MACHINE 5 Sheets-Sheet 2 Filed March 28, 1961 INVENTOR. Jasep/z {anal i July 5, 1966 J. GONSKI 3,259,435

CONTINUOUS MINING MACHINE Filed March 28, 1961 5 Sheets-Sheet 5 m m m M R mm W fl/ Q United States Patent f 3,259,436 CONTINUOUS MINING MACHINE Joseph Gonslri, Chicago, Ill., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Filed Mar. 28, 1961, Ser. No. 98,912 9 Claims. (Cl. 299-57) This invention relates to improvements in continuous mining and loading machines arranged for mining and loadig thin seams of coal in a continuous operation.

A principal object of the invention is to provide an improved form of continuous mining and loading machine having a pair of rotary boring heads mining a coal seam by endwise movement transversely of the coal seam toward each other together with a simplified form of gathering mechanism advancing with the mining heads, and gathering the mined material for loading.

Another object of the invention is to provide a simple and compact form of combined mining and loading machine, in which rotary boring heads are carried on the ends of boom arms and rotate about axes extending transversely thereof and are sumped endwise into the coal seam by advance of the machine toward a working face and are fed arcuately across the coal scam in generally endwise directions, and in which improved gathering and cusp removing devices are movable with the boom arms during the mining operation and are so arranged as to remove the cusps upstanding from the mine floor, during a mining and loading operation.

A further object of the invention is to provide a continuous mining and loading machine having an improved form of loading head including a rotatable boring arm providing clearance between the boring arm and mine roof and mine floor when in a horizontally extending position, to accommodate free retractible movement of the boring head at the termination of a boring operation.

A still further object of the invention is to provide an improved form of continuous mining and loading machine including a rotary boring head having a pair of opposed boring arms with a deflecting shield mounted inwardly of the boring head to advance the cuttings inwardly toward the center of the machine during the boring operation, in which the deflecting shield has a retractible upper end portion retractible when drawing the boring head from the working face.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a top plan view of a continuous mining machine constructed in accordance with the principles of the present invention with the mining heads in their inwardly extended positions, at the termination of the operation of mining and loading a seam of coal and the like;

FIGURE 2 is an enlarged fragmentary sectional view of the machine taken substantially along line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged partial fragmentary top plan view of the forward end portion of one side of the machine shown in FIGURE 1, with the mining head swung inwardly toward the center of the machine and with certain parts of the forward end portion of the machine broken away;

FIGURE 4 is an enlarged fragmentary sectional view taken substantially along line 44 of FIGURE 3, show ing the drive to a gathering and cusp cutting device;

FIGURE 5 is an enlarged fragmentary sectional view taken substantially along line 5-5 of FIGURE 3 and showing the support for a mining head on its boom arm and the means for adjusting the elevation thereof;

FIGURE 6 is a fragmentary side elevational view of one of the mining heads, showing the boring arms in 3,259,436 Patented July 5, 1966 "ice horizontally extending positions to provide clearance between the mine roof and the mine floor, and showing the associated pusher plate in a retracted position, to accommodate retractible movement of the mining head; and

FIGURE 7 is a front end view of the pusher plate shown in FIGURE 6.

In the embodiment of the invention illustrated in FIG- URE 1 of the drawings, I have shown a continuous mining machine 10 of the rotary boring head type. The mining machine 10 has two angularly movable rotary boring heads 11 adapted to cut and load an entire seam of coal by endwise movement along a coal face towards each other. The boring heads 11 are supported on the ends of vertically pivoted boom arms 12 for rotation about axes extending transversely thereof, and are adapted to be sumped endwise into the working face of a seam of coal, and the like, along opposite ribs of the working place, when in the laterally extended positions illustrated by dotted lines in FIGURE 1, by advancing the entire machine toward the working face. The mining heads 11 then mine the working face by feeding said boom arms and mining heads toward each other across the working face in fixed arcuate paths.

The mining machine 10 includes generally a main frame 13 mounted on the usual laterally space-cl continuous traction tread devices (not shown) for propelling the machine from working place to working place and for advancing the machine toward a working face, to feed the rotary boring heads 11 therein along opposite ribs of the working place, when in the laterally extended positions shown by dotted lines in FIGURE 1.

The continuous traction tread devices may be of a well known form and may be independently driven in a suitable manner well known to those skilled in the art, and are no part of the present invention so need not herein be shown or described.

Extending along the central portion of the main frame 12 is a laterally flexible single strand chain and flight conveyor 15 extending from a ground engaging shoe 16, having a wedge-like material carrying upper surface 17, along which the material is advanced onto said conveyor by gathering devices 19 movable with the boom arms 12, upon lateral feeding movement of the boring heads 11 across the working face of a mine. The conveyor 15 extends from beneath the upper extremities of the wedgeshape face 17 in an upwardly inclined direction over the top of the machine and has a laterally swingable rear end portion 20, swung from side to side and maintained in the desired position with respect to the centerline of the machine by fluid pressure operated jacks 21, in a conventional manner.

The boom arms 12 are pivotally mounted on vertical pivot pins 22 at the forward end portion of the main frame 13 at opposite sides of the conveyor 15. As shown in FIGURE 2, the boom arms 12 have rear bifurcated portions 23 extending along the upper and lower sides of bosses 24 formed integrally with the forward end portion of the main frame 13 on opposite sides of the conveyor 15.

The boom arms 12 and rotary boring heads 11 are swung about the axes of the vertical shafts 22 by hydraulic jacks 25 pivoted at their rear ends to brackets 26 on vertical pivot pins 27. The hydraulic jacks 25 are herein shown as being two stage hydraulic jacks and include piston rods 29 pivotally connected with the boom arms 12 by pivot pins 30 extending through ears 31 projecting laterally of said boom arms. Fluid under pressure may be admitted to the head or piston rod ends of the hydraulic jacks 25 under the control of fluid pressure control valves 33 connected with said jacks through suitable piping connections, to swing the boom arms 12 and rotary boring heads 11 toward and from each other and to hold said rotary boring heads in the laterally extended sumping positions shown in FIGURE 1. The fluid pressure system including the valves, piping and pump are no part of the present invention so need not be shown or described further. I

The boom arms 12 are of a generally dog leg form in plan and each have a portion 34 extending from the pivot pin 22 angularly forwardly and outwardly of the main frame 13, when the rotary boring head is in the inwardly extended position shown in FIGURES 1 and 3. Each boom arm 12 also has a forward end portion 35 and generally parallel to the longitudinal axis of the machine, when the rotary boring heads are in their inwardly extended positions. The forward end portion 35 has a bottom plate 36 (FIGURE 5) extending in advance of a front wall 37 of the forward end portion 35. Parallel spaced cars 39 extend upwardly from the bot tom plate 36 and forwardly of the front wall 37 and form a support for the pivot pin 49, forming a pivotal support for a cutter frame 41 rotatably supporting an associated boring head 11. As shown in FIGURES 1, 3 and 5, the cutter frame 41 has a pair of parallel spaced ears 42 extending rearwardly of a rear wall 43 of said cutter frame and extending inwardly of the ears 39 and pivotally mounted on the shaft 40.

A hydraulic jack 44 is pivotally connected between two spaced connector lugs 45 extending forwardly of the junction of the bottom plate 36 with the wall 37, on a transverse pivot pin 46. The hydraulic jack 44 has a piston rod 47 extensible therefrom pivotally connected between two parallel spaced connector lugs 49 extending rearwardly of the rear wall 43 adjacent the lower end portion thereof. A pivot pin 50 is provided to connect the piston rod 47 to the lugs 49. The hydraulic jack 44 thus serves to elevate and lower the cutter frame 41 and rotary boring head 11, rotatably supported thereon, and to hold said cutter frame and rotary boring head in fixed relation with respect to the ground in an obvious manner.

Each boom arm 12 also has an apron 53 extending therealong and forming a support for a gathering device 19. As shown in FIGURES 3 and 4, the apron 53 is inclined downwardly from the boom arm 12 toward the ground and has slidable engagement with the ground at its inner end. The apron 53 overlaps the wedge shaped face 17 of the shoe 16 at its rear end portion and ex tends forwardly therefrom along the boom arm 12 to a position adjacent the forward end portion thereof. The apron 53 has a beveled inner face 54 extending for the length thereof and terminating at its lower end into a plane blade or chisel-like edge slidably movable along the ground, which serves to plane or chisel the cusps left from a next preceding mining operation, as the boom arms 12 are moved inwardly toward each other to feed the rotary boring heads 11 across a working face of a mine.

The apron 53 also has an angular edge 55 connecting the forward end portion of the beveled face 54 with a forward end portion 56 of said apron. Plates 57 and 58 extend downwardly from the edge portions 55 and 56 into engagement with the ground and form in effect bulldozer blades progressing the mined material onto said apron during inward feeding movement of the boom arms 12. A retainer plate 59 extends upwardly of the outer side of the apron 53 along the inner car 39 and angularly inwardly and forwardly therefrom to a position adjacent the forward end portion of the plate 58. The retainer plate 59 then extends forwardly of the plate 58 into slidable abutting engagement with a pusher plate 60 mounted on the inner face of the cutter frame 41 and backing up an associated rotary boring head 11. The plates 57 and 58 being inclined with respect to the ground and having chisel-like edge portions engageable with the ground, besides serving as bulldozers for the mined material also serve to trim or level off the cusps projecting upwardly from the mine floor and left by the rotary boring heads 11 in a preceding mining operation.

Each gathering device 19 includes an orbitally guided endless chain 61 having gathering arms 62 extending outwardly therefrom and pivotally connected thereto between spaced lugs 63 on pivot pins 64. The gathering arms 62 are of a well known form and have cutter bits 65 projecting therefrom. The cutter bits 65 extend in advance of the beveled face 54 and serve to trim the cusps upstanding from the mine floor prior to leveling the mine floor by the beveled edge 54 of the apron 53. The endless chain 61 is guided in a channeled guide 66, extending about a cutter bar 67 mounted on the top surface of the apron 53. The cutter bar 67 may be of a well known construction so need not herein be shown or described further,

The endless chain 61 meshes with and is driven by a sprocket 69 mounted intermediate the ends of a drive shaft 70 journalled in .the cutter bar 67 on anti-friction bearings 71. The drive shaft 79 is shown in FIGURE 4 as having a bevel gear 73 keyed or otherwise secured to its lower end portion and meshing with and driven from a bevel pinion 74 on the inner end of a generally transverse drive shaft 75, spaced beneath and extending at the angle of the apron 53. The drive shaft 75 is journalled adjacent its lower end inwardly of the bevel pinion 74 in a housing 76 enclosing the bevel gear 73 and bevel pinion 74. The drive shaft 75 extends angularly upwardly of the bevel pinion 74 within the boom arm 12 and is journalled in said boom arm in a bearing support 77 extending angularly upwardly of the bottom plate 36 of said boom arm. A spur pinion 79 is keyed or otherwise secured to the outer end of the drive shaft 75, adjacent the bearing support 77, and meshes with and is driven from a bevel motor pinion 80 on the end of the motor shaft 81 of a drive motor 83, suitably mounted within the boom arm 12. The drive motor 83 may be of any well known form, but is herein preferably shown as being a fluid operated motor.

The gathering arms 62 have inner abutment faces 84 engaging beveled cam faces 85 formed on a lower plate 86 of the cutter bar for pivoting the gathering arms upwardly as they reach the wedge face 17 of the shoe 16 and turn about the sprockets 69, to avoid the progressing of material around the cutter bar 67 and away from the conveyor 15.

Referring now to the rotary boring heads 11 and the support and drive for said boring heads, each boring head has a hub 87 mounted on a shaft 88 journalled in the cutter frame 41 and extending within said cutter frame transversely of the associated boom arm 12.

A motor 89, which may be a well known form of electric motor is mounted on and projects from the opposite side of the cutter frame 41 from the boring head 11 and has a motor pinion 90 within the cutter frame 41, which has driving connection with the shaft 88 through a reduction gear train 91.

The hub 87 has two aligned radial arms 93 extending therefrom having cutter supports 94 on the outer ends thereof. The cutter supports 94 generally conform to the arc of rotation of the boring head and have cutter bits 95 projecting therefrom. The arms 93 have central pilot cutter supports 96 projecting forwardly therefrom inwardly of the cutter supports 93 and carrying cutter bits 97 for making a pilot cut and breaking down the core within said cutter supports during the mining operation.

Each radial boring arm 93 has a boring arm 99 projecting laterally therefrom and extending generally perpendicular to a radial line extending through the center of the associated radial arm 93. The boring arms 99 extend in opposite directions with respect to each other and have cutter supports 1th] on the outer ends thereof having cutter bits 101 projecting outwardly therefrom. The cutter supports 10!) are arcuate in front end view and conform generally to the arc of travel of the boring arms 99. The arms 99 have impeller blades 102 extending inwardly therefrom toward the pusher plate 60. The blades 102 cooperate with the boring arms 99 and pusher plate 60, to impel the mined material towards the gathering devices 19, it being understood that the boring heads 11 rotate towards the gathering devices 19 along the floor of the mine.

A means is provided to vary the cutting diameter of the boring head, which is herein shown as comprising two parallel spaced rows of holes 103 in the boring arms 99. Certain of said holes are adapted to register with corresponding holes (not shown) in the radial arms 93. Cap screws 104 may register with the associated holes and be threaded within the associated radial arm 93 for securing the boring arm 99 thereto at a preselected cutting diameter.

In FIGURE 2, I have shown the boring arms 99 in position to cut at one cutting diameter and have indicated by broken line A a larger cutting diameter for the boring head. While in the present disclosure, the broken line A is the maximum cutting diameter of the boring head, it may readily be understood that the lengths of the boring arms 99 may be increased by substituting longer boring arms where required to cut at greater cutting diameters than the cutting diameter shown by broken line A. Broken line B indicates the minimum cutting diameter of the boring head when the boring arms 99 are in their extreme retracted positions. It should further be understood that upon removal of the boring arms 99 the boring arms 93 may determine the cutting diameter of the boring head.

The pusher plate 60 is shown in FIGURE 7 as having a slot 105 therein and as having a row of drilled holes 106 on each side of said slot accommodating the pusher plate to be secured to the advance face of the cutter frame 41 by cap screws 107, it being understood that the slot 105 accommodates the shaft 88, making it possible to readily detach the pusher plate 60 from the cutter frame 41.

The pusher plate 60 has a hinged sector 109 extending along the upper end portion thereof and hinged thereto as by hinge members 110. The hinge sector 109 is retained in aligned relation with respect to the pusher plate 60 and is retracti-bly moved with respect to said pusher plate when it is desired to retractibly move the associated boring head at the termination of a mining operation by a hydraulic cylinder and piston 111 pivotally connected to the top of the cutter frame 41 at one end and pivotally connected to the back of the sector 109 at its opposite end as shown in FIGURES 3 and 6.

The pusher plate 60 conforms generally to the cutting diameter of the rotary boring head 11 and may be replaced with pusher plates of varying diameters as the cutting diameter of the boring head is varied, to accommodate the pusher plate to advance with the boring head into the arcuate bore in the mine face and progress the broken down material to be progressed by the boring arms 99 toward the gathering devices 19, to be picked up thereby.

It will here be noted that when the boring arms 99 are positioned in horizontal relation with respect to the ground as shown in FIGURE 6, that substantial clearance is provided between the boring head and the floor and roof of the mine seam. Thus, when it is desired to retract the boring heads, they are stopped when the arms 99 are in their horizontal positions, to provide clearance therefor. The hinged sector 109 is then retracted by the hydraulic cylinder and piston 111 to the position shown in FIGURE 6 and the cutter frame 41 is elevated by operation of the hydraulic jack 44 to lift the bot-tom of the pusher plate 60 above the mine floor. The boring heads may then be readily retracted, by operation of the hydraulic jacks 25, into position to effect a next succeeding boring operation.

In mining a thin seam of coal with the continuous mining machine herein described, assuming the boring arms 99 have been adjusted to mine the entire seam from the floor to the roof of the mine, and that the pusher plates generally conform to the cutting diameters of the boring heads, and that the boring arms 99 are positioned to extend horizontally and the sectors 109 have been retracted, the boom arms 12 are swung outwardly to the dotted line positions shown in FIGURE 1 with the cutter bits 101 positioned to cut along opposite ribs of the working place.

The sectors 109 are then extended to the vertical positions shown in FIGURE 6, the cutter frames 41 having first been lowered to position the pusher plates 60 adjacent the mine floor.

The motors 41 are then started to operate the mining heads to rotate in the same directions and to progress the mined material toward the gathering devices 19. Assuming that the conveyor 15 is in operation, and that the motors 83 have been started to drive the gathering devices to progress the mined material to the conveyor 15, power may be applied to the continuous traction tread devices (not shown) to advance the rotary boring heads along the ribs of the working place and to sump said rotary boring heads into the working face along the ribs thereof to a selected cutting depth.

When the rotary boring heads have advanced along the ribs of the working place into the working face to the required depth, they may then be fed transversely across the working face about the vertical shafts 22 by operation of the hydraulic jacks 25.

During the advance or sumping of the boring heads along opposite ribs of the working place and during arcuate swinging movement of the boring heads across the working face to mine the working face, the cutter bits moving in advance of the beveled edge 54 of the apron 53 will trim the cusps left from a preceding mining operation, while the beveled edges 54 and inclined plates 57 and 58 of the apron 53 will plane or chisel the portions of the cusps not cut or broken down by the cutter bits 65 and provide a clean level floor. The retainer plates 59 and pusher plates 60 will also cooperate with the rotary boring heads and inclined plates 57 and 58 to progress the mined material toward the gathering devices to be picked up thereby.

As the working face is mined and the boring heads reach the solid line position shown in FIGURE 1, the boring heads are then positioned with the boring arms 99 in horizontal relation with respect to the ground.

The sectors 109 are then retracted by operation of the hydraulic cylinders and pistons 111 and the boring heads are then retracted to the dotted line positions shown in FIGURE 1 and are then positioned to again be sumped along the ribs of the working face and fed inwardly across the face in the manner just described.

While I have herein shown and described one form in which my invention may be embodied, it may readily be understood that various modifications and variations in the invention may be attained without departing from the spirit and scope of the novel concepts of the invention as defined by the claims appended hereto.

I claim as my invention:

1. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from one end thereof to the other, a pair of boom arms pivotally mounted on said main frame adjacent the forward end thereof for movement about vertical axes on opposite sides of said conveyor, a boring head rotatably carried by each boom arm, means for rotatably driving said boring 'heads, means feeding said boom arms and .boring heads about the axes of connection of said boom arms to said main frame, and gathering means mounted on said boom arms for movement therewith comprising aprons mounted on and extending along the inner sides of said boom arms and inclined downwardly from said boom arms into scraping engagement with the ground, and or-bitally traveling gathering devices mounted on said aprons for advancing the mined material onto said conveyor and trimming the cusps upstanding from the mine floor during the operation of advancing the mined material toward said conveyor.

2. A continuous mining machine in accordance with claim 1, wherein the gathering devices comprise orbitally guided endless igathering'chains guided for movement along said aprons having gathering arms projecting laterally therefrom having cutter bits mounted therein and projecting therefrom for trimming the cusps projecting upwardly of the mine floor in advance of said aprons during movement of said aprons toward the longitudinal center of the machine.

3. A continuous mining machine in accordance with claim 2, wherein the aprons have beveled advance and front edges having slidable engagement with the ground, for progressing the mined material into the path of said gathering arms and for planing the trimmed cusps left on the mine floor.

4. A continuous mining machine in accordance with claim 1, wherein aprons extend along the inner sides of said boom arms and are inclined from said boom arms into engagement with the ground along their inner advance edges, wherein the inner advance edges of said apron are beveled to have scraping engagement with the ground, wherein inclined plate members connect the forward end portions of said aprons with the ground to provide pusher surfaces having scraping engagement with the ground and advancing the mined material onto said aprons, wherein gathering chains are guided for orbital movement about said aprons and have gathering arms projecting therefrom, and wherein said gathering arms have cutter bi-ts projecting therefrom into close proximity to the ground, to cut and break off the cusps projecting upwardly of the ground, left from a preceding mining operation, to be planed smooth by the advance beveled edges of said aprons during advancing of said aprons along the mine floor toward each other.

5. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from one end thereof to the other, a pair of boom arms pivotally mounted on said main frame adjacent the forward end thereof for movement about vertical axes at opposite sides of said conveyor, a boring head rotatably carried by each boom arm for rotation about a horizontal axis generally tangential to the arc of swinging movement of the associated boom arm, individual motors for driving said boring heads, aprons extending along said boom arms on the insides thereof and inclined downwardly from said boom arms into slidable engagement with the ground, said aprons having beveled advance faces having planing engagement with the ground, inclined front faces adjacent said boring arms for progressing the mined material onto said aprons, and angular beveled faces connecting said front and side faces together and cooperating therewith to plane the mine bottom and progress the mined material onto said aprons, and gathering devices guided for orbital travel along said aprons from positions adjacent said conveyor, said gathering devices including endless gathering chains having gathering arms projecting laterally from said chains and having cutter bits projecting therefrom for trimming the cusps upstanding from the mine floor in advance of said beveled advance planing faces of said aprons.

6. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from a position adjacent the ground at the forward end of said main frame, a pair of boom arms extending in advance of said main frame, means mounting said boom arms on said main frame for pivotal movement about vertical axes at opposite sides of said conveyor, power means for moving said boom arms toward and from each other about said vertical axes, a rotary boring 'head carried by each boom arm, each boring head including .a cutter frame mounted on said boom arm for vertical adjustable movement about an axis extending transversely of said boom arm, a bearing support for said boring head on the inner side of said cutter frame and supporting said cutter frame for rotatable movement about an axis parallel to said transverse axis and generally tangential to the arc of travel of said boring head, a motor mounted on said cutter frame on the opposite side thereof from said boring head and having drive connection with said boring head and rotatably driving said boring head to rotate upwardly from the ground towards said conveyor, hydraulic cylinder and piston means interposed between said boom arms and cutter frames for retaining said cutter frames in position with respect to said boom arms and vertically adjustably moving said cutter frames about the axes of said transverse shafts, and pusher plates mounted on the inner faces of said cutter frames behind said boring heads and conforming substantially to the bores cut by said boring heads and retaining the mined material to said boring heads to be progressed towards said conveyor by said boring heads.

7. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from a position adjacent the ground at the forward end of said main frame, a pair of boom arms extending in advance of said main frame, means mounting said boom arms on said main frame for pivotal movement about vertical axes at opposite sides of said conveyor, power means for moving said boom arms toward and from each other about said vertical axes, a rotary boring head carried by each boom arm, each boring head including a cutter frame mounted on said boom arm for vertical adjustable movement about an axis extending transversely of said boom arm, a hearing support ,for said boring head on the inner side of said cutter frame and supporting said cutter frame for rotatable movement about an axis parallel to said transverse axis and generally tangential to the arc of travel of said boring head, a motor mounted on said cutter frame on the opposite side thereof from said boring head and having drive connection with said boring head and rotatably driving said boring head to rotate upwardly from the ground towards said conveyor, hydraulic cylinder and piston means interposed between said boom arms and cutter frames for retaining said cutter frames in position with respect to said boom arms and vertically adjustably moving said cutter frames about the axes of said transverse shafts, and pusher plates mounted on the inner faces of said cutter frames behind said boring heads and conforming substantially to the bores cut by said boring heads and retaining the mined material to said boring heads to be progressed towards said conveyor by said boring heads, said pusher plates each having a retractible top portion retractible to accommodate vertical movement of said boring heads upon withdrawal of said boring head from the working place, and hydraulic cylinder and piston means retractibly moving said retractible portions of said pusher plates and retaining said retractible portions in vertical alignment with said pusher plates.

8. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from a position adjacent the ground at the forward end of said main frame, a pair of boom arms extending in advance of said main frame, means mounting said boom arms on said main frame for pivotal movement about vertical axes at opposite sides of said conveyor, power means for moving said boom arms toward and from each other about said vertical axes, a rotary boring head carried by each boom arm, each boring head including a cutter frame mounted on said boom arm for vertical adjustable movement about an axis extending tranversely of said boom arm, a bearing support for said boring head on the inner side of said cutter frame and supporting said cutter frame for rotatable movement about an axis parallel to said transverse axis and generally tangential to the arc of travel of said boring head, a motor mounted on said cutter frame on the opposite side thereof from said boring head and having drive connection with said boring head and rotatably driving said boring head to rotate upwardly from the ground towards said conveyor, said boring heads each having at least two parallel boring arms extending in opposite: directions from a diametral line extending through. the center of said boring head and clearing the roof and floor of the mine when in a horizontally extended position, to accommodate withdrawal of said boring heads by retractible movement of said boom arms, when said boring arms are positioned horizontally with respect to the mine bottom.

9. In a continuous mining machine, a mobile main frame, a conveyor extending along said main frame from a position adjacent the ground at the forward end of said main frame, a pair of boom arms extending in advance of said main frame, means mounting said boom arms on said main frame for pivotal movement about vertical axes at opposite sides of said conveyor, power means for moving said boom ar-ms toward and from each other about said vertical axes, a rotary boring head carried by each boom arm, each boring head including a cutter frame mounted on said boom arm for vertical adjustable movement about an axis extending transversely of said boom arm, a bearing support for said boring head on the inner side of said cutter frame and supporting said cutter frame for rotatable movement about an axis parallel to said transverse axis and generally tangential to the arc of travel of said boring head, a motor mounted on said cutter frame on the opposite side thereof from said boring head and having 30 drive connection with said boring head and rotatably driving said boring head to rotate upwardly from the ground towards said conveyor, said boring heads each having at least two parallel boring arms extending in opposite directions from a diametral line extending through the center of said boring head and clearing the roof and floor of the mine when in a horizontally ex' tended position, to accommodate withdrawal of said boring heads by retractible movement of said boom arms, when said boring arms are positioned horizontally with respect to the mine bottom, and pusher plates mounted on said cutter frames rearwardly of said boring heads and conforming generally to the bores cut by said boring heads, said pusher plates each having a retractible upper end portion retractible to accommodate elevation of said boring heads when said boring arms are positioned horizontally with respect to the mine bottom, to accommodate free retractible movement of said boring heads, and cylinder and piston means for moving said retractible portions of said pusher plates in retracted or aligned relation with respect to said pusher plates.

References Cited by the Examiner UNITED STATES PATENTS 1,361,996 12/ 19 20 Hirst 299-64 2,283,212 5/1942 Joy 299-31 2,734,732 2/1956 Tracy 29980 2,776,823 1/1957 Barrett 299-73 2,933,294 4/1960 Meehan 299-64 3,052,454 9/1962 Sibley 299-71 3,210,123 10/1965 Delli-Gatti 299-64 ERNEST R. PURSER, Primary Examiner.

BENJAMIN HERSH, JACOB L. NACKENOFF,

Examiners. 

1. IN A CONTINUOUS MINING MACHINE, A MOBILE MAIN FRAME, A CONVEYOR EXTENDING ALONG SAID MAIN FRAME FROM ONE END THEREOF TO THE OTHER, A PAIR OF BOOM ARE PIVOTALLY MOUNTED ON SAID MAIN FRAME ADJACENT THE FORWARD END THEREOF FOR MOVEMENT ABOUT VERTICAL AXES ON OPPOSITE SIDES OF SAID CONVEYOR, A BORING HEAD ROTATABLY CARRIED BY EACH BOOM ARM, MEANS FOR ROTATABLY DRIVING SAID BORING HEADS, MEANS FEEDING SAID BOOM ARMS AND BORING HEADS ABOUT THE AXES OF CONNECTION OF SAID BOOM ARMS TO SAID MAIN FRAME, AND GATHERING MEANS MOUNTED ON SAID BOOM ARMS FOR MOVEMENT THEREWITH COMPRISING APRONS MOUNTED ON AND EXTENDING ALONG THE INNER SIDES OF SAID BOOM ARMS AND INCLINED DOWNWARDLY FROM SAID BOOM ARMS INTO SCRAPING ENGAGEMENT WITH THE GROUND, AND ORBITALLY TRAVELING GATHERING DEVICES MOUNTED ON SAID OPRONS FOR ADVANCING THE MINED MATERIAL ONTO SAID CONVEYOR AND TRIMMING THE CUSPS UPSTANDING FROM THE MINE FLOOR DURING THE OPERATION OF A ADVANCING THE MINED MATERIAL TOWARD SAID CONVEYOR. 